Xerography
Xerography is a method of electrostatic copying that was developed in the mid-20th century, notably by Chester F. Carlson. The term, derived from Greek meaning "dry writing," emerged in 1948 to describe this innovative process, which primarily involves the use of a photoconductive surface that can be charged electrostatically. Initially, Carlson demonstrated his technique using a sulfur-coated zinc plate, but subsequent advancements introduced selenium as the photoconductive medium and improved toner compositions.
The collaboration between Carlson and the Battelle Institute led to significant enhancements in the technology, culminating in a licensing agreement with Haloid Corporation, which sought to diversify its offerings. The first commercial copier, the Model A, was introduced in 1949, but it wasn't until the release of the Model 914 in 1959 that xerography truly revolutionized the document-copying industry. This model was highly successful, leading to widespread use and substantial financial success for its inventors and stakeholders, including the transformation of Haloid into Xerox. Today, xerography remains a foundational technology in modern printing and copying.
Xerography
Patented method for document copying
During the 1940’s document copying involved complicated photographic methods or hand typing of stencils. Xerography, which began during the 1940’s and came to full fruition during the 1960’s, permitted rapid copying without the use of liquid chemicals.
By 1940, Chester F. Carlson had demonstrated his method of electrostatic copying, or “electrophotography” as he called it, on a small scale. With an assistant he hired at his own expense, he developed a sort of kit that he could use to show his process to others. At the heart of his method was a photoconductive layer of sulfur on a zinc plate. The sulfur layer could be electrostatically charged by rubbing it with a silk cloth. Seeking sponsors for further development, Carlson contacted companies such as International Business Machines (IBM), the Charles Bruning Company, and several others without obtaining any definite commitments. In 1944, Carlson contacted the Battelle Institute in Columbus, Ohio, and made a favorable impression with his demonstration.
Battelle Institute was an independent research facility whose scientists and engineers generally took on specialized projects for industrial clients. In 1942, however, the institute made an agreement with Carlson to develop electrophotography in return for a share of future royalties. At Battelle, some fundamental improvements were soon made to Carlson’s methods. Electrostatic charging of the photoconductive plate could be done by corona discharge, and selenium was used as the photoconductive medium. Also, advances were made in the composition of the toner powder and to the means of transferring it to the photoconductive layer; as a result, the means of transference to paper also improved. Around this time, Carlson’s work attracted journalistic attention; Nicholas Langer wrote an article for Radio News magazine based on an interview with Carlson and presented his ideas in a favorable light. Langer’s article came to the attention of management at Haloid Corporation in Rochester, New York, a supplier of photographic paper to Eastman Kodak. Haloid sought to diversify its business. Soon, Battelle and Haloid had a licensing agreement, and Carlson moved to Rochester to act as a consultant. Research continued at Battelle, and slowly began at Haloid, encouraged by Haloid’s chairman, Joseph Wilson.
In 1948, the term “xerography” replaced “electrophotography.” The new term was suggested by a classics professor and had its origin in the Greek for “dry writing.” The occasion for the change was a meeting of the Optical Society of America, where Battelle and Haloid presented a joint paper on the new science. However, at this point, there was no device to be unveiled or sold. In 1949, the Model A copier was introduced. This was not a successful document copier, but it did well at creating multilith masters.
Impact
The full impact of xerography was felt with the introduction of the model 914 copier in 1959. This model has been called the most successful product introduction in the twentieth century. The copiers were leased, not sold, and a fee was charged for each copy made. Soon, millions of copies were printed, and Carlson, as well as many other shareholders of Haloid, which had changed its name to Xerox, became millionaires.
Bibliography
Dessauer, J. My Years with Xerox: The Billions Nobody Wanted. New York: Doubleday, 1971.
Mort, J. The Anatomy of Xerography: Its Invention and Evolution. Jefferson, N.C.: McFarland, 1989.
Owen, David. Copies in Seconds. New York: Simon & Schuster, 2004.